Improvement in furnaces for the manufacture of ultramarine



am ma.

.-HnNnrA. LUDWIG, on NEW Yoan, N. Y.

Letters Patent No. 97,940, dated December 14, 1869. y

. IMPROVEMENT IN PURNACES PoR THE MANUFACTURE .or ULTRAMARINE.

The Schedule referred to in theseLettera Patent and making part of the same i had to the accompanying. drawing, forming part of `this specification, and'in which-. i

Figure l represents a centrally vertical longitudina `section of a double oven, constructed in accordance -with -uiy improvement, and

i' Figure 2, a a'el'tical transverse section thereof,v

through the line are in tig. 1. p

Similar letters of reference `indicate corresponding parts. y

' My improvement has reference to the manufacture of artificial ultramarine, and though more particularly designed for making that article from a mixture or compound which I regard as superior to any other for the purpose, and which `is made the subject of a separate application for Letters Patent, said invention is.

not restricted thereto, but Vmay be .used for ,making the article from other compounds, such as, for instance,

y the mixtures ordinarily used.

Heretofore it has been customary to place the'compound or mixture in crucibles, and gradually heat up the same, till acquiringa `re`d heat, for a lengthened period, in a suitably-constructed oven,` and afterwards withdraw the crucibles` from said oven, and taking out `the fused or partly fused mass, subsequently-to suitably pound 'or `prepare it, and then place the `same in Va second oven, heated, by a separate lire, to a lower temperature than the` first oven,for asuiiicient length of timeito desulphurize y the mass, that afterwardsis properly and variously treated. i i

In thus using separate ovens, heated by separate lires, there is not only great waste of fuel, and much `labor in attending to the tires, but the process of making ultramarine in large quantities is necessarily a fof the mass as hcreinbefore recited.

'up into the oven B, through a longitudinal central opening, a, made vin they bottom of said oven, and,

after disseminating, through the latter' among thek crucibles containing the mass to be treated, escaping, by side-fines b, from or neal the bottom of said lower oven, up into the upper oven O, and thence, through end-openings c in the roof` of the latter, into an escape-flue vor passage, D. p

These crucibles containing the mass are first put into the lower and hottest oven B, on either side of the central opening a, and having thus been exposed to the requisite high temperature for a suliicieiit length of time, (the heat gradually increasing, and afterwards subsidiug,) are taken ont of `said oven B, and th mass, after having been pounded or prepared, pnt in iron vessels, within the upper and cooler oven C, or spread out outhe bottom of said oven, for the purpose of desulphurization, and where it is allowed to remain f while a fresh charge of the compound or mixture is undergoing fusion or treatment in the lower oven B, so that the one tire serves to keep both ovens at their proper rela-tive temperatures, and much time and -labor is saved, the desulphurizing=process of a previous charge going ou at the same time that a new charge is being fused or treated in thel lowerand hotter oven; nor need the furnace be opened, to take out the charge .from the upper oven, till the charge in the lower oven i has been fully and properly treated.

In this way is secured not only economy of fuel, but a much larger quantity of `material may be treated in a given time, and with less labor.

Ilurthermore, the manner in which the heat is introduced into l[he lower oven, and divided up in its escape therefrom, on opposite sides, by the llues'b, from the bottom of said oven to opposite sides of the upper oven, added to the arrangel'nex'it of the ovens one above the other, insures an eqnalizing action of thehea't on the masses in the two ovens, at a proper herein set forth.

` HENRY A., LUDWIG.

Witnesses:

FRED. HAYNEs, HENRY PALMER. 

